This invention provides a metered-dose inhaler comprising a medicament-containing vessel, an actuator body for releasably attaching the vessel to the body and having a medicament delivery outlet, a dose counter integrated into the actuator body; and indicia on the vessel and the actuator body, said indicia identifying the vessel and the actuator body to be part of the same metered-dose inhaler. Also provided is a kit comprising the medicament-containing vessel, the actuator body, the dose counter and at least one pair of stickers releasably attached to a backing sheet and comprising a first sticker and the second sticker which can be identified as being part of the pair. The invention further provides a method for manufacturing the metered-dose inhaler comprising the steps of providing the medicament-containing vessel, providing the actuator body, releasably attaching the vessel to the actuator body, and subsequently attaching a first indicium to the vessel and a second indicium to the actuator body, such that the first indicium and the second indicium identify the vessel and the actuator body to be part of the same metered-dose inhaler.
Commonly the contents of the medicament-containing vessel are not visible by the user, for example, when the inhaler is a pressurised metered-dose inhaler (of both manually-operable and breath-actuated types) or dry-powder inhalers.
One of the drawbacks of self-administration using an inhaler is that users often experience difficulty in determining when the medicament in the medicament-containing vessel (canister) is nearly exhausted. With aerosol canisters, part of the reason for this difficulty is that a surplus of propellant may remain in the canister even though the medicament supply is nearly used up. This leads the user to believe that the inhaler is still capable of providing useful doses of medicament simply because the canister contains liquid. Alternatively, the near-exhausted state may result in a surplus of medicament in relation to propellant.
The prospect of the medicament unexpectedly running out is potentially hazardous for the user because the delivered dose becomes variable towards the end of the dosing regime. Likewise few users routinely carry a second back-up inhaler on them.
One strategy used by users is to have several different inhalers that are kept at a different locations, such as at school, home, work etc. In these circumstances it is particularly difficult for the user to keep track of the amount of usage extracted from each individual inhaler.
Clearly there is a need for a counter mechanism which enables users to assess how many doses remain in the obscured vessel. Such a counter would ensure that users are warned when the inhaler nears exhaustion so that appropriate measures can be taken to avoid running out of medication.
Recognising this risk, in March 2003 the US Food and Drug Administration issued a Guidance for Industry document (Integration of Dose-Counting Mechanisms for Metered-Dose Inhaler Medicament Products), which set out the requirement that all new metered-dose inhalers are required to have a dose counter in order to allow the patient to see how many doses remain in the inhaler. This requirement relates to all new inhalers for the US market, and hence is an important consideration for all manufacturers.
Several methods for counting the remaining doses in metered-dose inhalers have been disclosed. EP 0 966 309, which is incorporated by reference, discloses a mechanical dose counter in which administration of a dose of medicament by the inhaler causes a visible display indicating the number of medicament doses remaining in the inhaler to decrease by one.
Specifically, EP 0 966 309 discloses a dose counter comprising actuator means; drive means for driving rotary gear means in step-wise fashion in response to displacement of said actuator means, said rotary gear means comprising a wheel mounted on a spindle and said wheel having a plurality of ratchet teeth around its periphery; means to prevent reverse rotation of said rotary gear means; display means coupled to the rotary motion of said rotary gear means, said display means having a visible array of incrementing integers on a surface thereof indexable by a single integer in response to each step of the step-wise rotary motion of the rotary gear means; and said dose counter further comprises a control surface to regulate the position of engagement and disengagement between said drive means and said wheel.
In the case of the dose counter described above, as is common in metered-dose inhalers, the dose counter is integrated into the actuator body of the metered-dose inhaler rather than the medicament-containing vessel. Further, the actuator body and the medicament-containing vessel of metered-dose inhalers are generally separable from each other.
Consequently, there is a risk that after separation of the actuator body and the medicament-containing vessel (for example when washing the actuator if it becomes clogged), the actuator body may be mismatched with a different medicament-containing vessel to the one to which it was previously attached. After mismatching, the dose counter would clearly not then accurately reflect the remaining number of doses in the medicament-containing vessel.
It is worthy of note that users often have multiple metered-dose inhalers, and therefore the risk of mismatching can be significant. Further, the consequences of a dose counter inaccurately reflecting the number of doses in the medicament-containing vessel could be severe, as this could result in a patient being without medication when needed. There is therefore a need in the art for a solution to this potentially hazardous problem.
WO2006/064159 A1, which is incorporated by reference, discloses a fluid dispenser device comprising: a reservoir of fluid to be disposed; a dispenser member, such as a pump or a valve, mounted on said reservoir; and a body that is suitable for receiving said reservoir, said body being provided with a dispenser orifice and an opening through which said reservoir can be inserted into the body, said reservoir can be inserted into the body between a rest position and a dispensing position, said reservoir being removable from said body; the device being characterised in that said reservoir and said body include respective ID means that make it possible to associate said reservoir with said body.
There is a need for improved solution to the problem of mismatching medicament-containing vessels and actuator bodies. Preferably the solution should have one or more of the following characteristics: 1) be safer and more reliable than existing methods; 2) allow for simpler, i.e. more economic, manufacture of the inhaler; 3) be easier for the patient to use, especially for children or visually impaired patients; 4) it should produce less detectable extractable and leachable substances than prior art methods in required tests for extractable and leachable substances performed for regulatory approval; and 5) be more reliable than those methods described in the art. There is also a need for improved methods of manufacturing devices of this type.